Ultrasound-assisted tomography systems of the type mentioned at the outset comprise an arrangement of ultrasonic transducers which are arranged around the object to be examined and the main radiation direction of which is directed towards the object.
DE 28 27 423 A1 describes a device for ascertaining the internal structure of a body using sonic beams, in which the body is introduced into a container filled with a coupling medium and is investigated using ultrasound in said container using the ultrasonic transmission process. Here, the ultrasonic transducers are arranged cylindrically in the container in a matrix.
Likewise, U.S. Pat. Nos. 5,673,697 and 4,478,083 disclose ultrasonic test systems for three-dimensional tomographic imaging of objects, in which systems the ultrasonic transducers are arranged in a matrix shape around a measurement volume.
DE 100 50 232 A1 describes, by way of example, a high-resolution ultrasonic tomograph, in particular for medical examinations, in which a body part to be examined, in particular a female breast, protrudes from above into an ultrasonic coupling medium in an open container. The container wall comprises securely arranged ultrasonic transducers oriented towards the interior of the container over the entire wall surface. Said transducers are controlled as transmitters or receivers either individually or in groups by means of a computer-assisted control and evaluation unit, the ultrasonic signals emitted by the transmitters being ultrasonic pulses. These are conducted to the body part to be examined, are manipulated at this point and are received in parallel by all the receivers in the form of reflection and transmission signals.
In general, when configuring ultrasound-assisted reflection and transmission tomography, the aim is to achieve the highest possible resolution by means of the densest possible distribution of cylindrical ultrasonic measurement heads over the surface of a hemisphere or, more generally, of a rotationally symmetrical half-ellipsoid around the object to be examined. In this case, due to the densest possible arrangement of the ultrasonic transducers, which are as similar as possible, the aim in principle is to position said transducers in a pattern or periodic arrangement relative to one another.